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Quite a few things in your morning pick-me-up: coffee poses a challenge to risk assessment

22/2016, 16.06.2016

Hazard based classification of limited informative value for consumers

Following the risk classification of coffee of 15 June carried out by the International Agency for Research on Cancer (IARC) located at the World Health Organisation (WHO), the German Federal Institute for Risk Assessment (BfR) points out that the risk assessment of complex mixtures such as foods are of only limited informative value for consumers. "Each food can regularly contain substances, though they typically only occur in traces, with carcinogenic potential. At the same time, however, health-promoting substances too have an effect on the organism", says BfR President Professor Dr. Dr. Andreas Hensel. "Foods such as coffee or meat are usually much too complex mixtures to allow general statements about their carcinogenic potential that would be of any practical use to consumers." In its study published in advance today, the IARC rates coffee as "not classifiable with regard to its carcinogenicity for humans" (Group 3).

Apart from various health-promoting substances, coffee also contains the type of active ingredients that, in isolation, can act as carcinogens in humans. Among these are, for example, furan, acrylamide and polycyclic aromatic hydrocarbons (PAHs). In addition, caffeine can have a negative effect on health. However, the totality of available studies does not prove any carcinogenic potential of coffee. As is the case with other foods, there are two reasons for the different effect of the isolated active ingredients and the food as a whole. On the one hand, it is possible that substances are contained in the food which mitigate or neutralise the potentially harmful effects of other substances. On the other hand, it is possible that the content of unwanted substances is so low that the available studies based on typical consumption do not show any harmful effects.

Since its inception, the IARC has investigated 989 chemicals, substances, foods or activities for their carcinogenic potential (according to IARC, as at February 2016). Among them, only one substance was classified as Group 4 as "probably not carcinogenic in humans". The classifications of the IARC are conducted independently of licensing and approval procedures. In contrast to the BfR which assesses the possible health risks, the IARC only assesses the hazard potential of a substance. In addition to the hazard potential, risk assessments also consider the actual intake (exposure).

The IARC published a summary of its monograph on hot drinks, mate tea and coffee in advance. In it, the IARC rates coffee as "not classifiable in terms of its carcinogenicity in humans" (Group 3), thereby changing its classification of coffee which back in 1991 it had graded as "possibly carcinogenic in humans" (Group 2B).

Independently of the classification of the carcinogenic potential of coffee, the BfR has repeatedly drawn consumers' attention to the health risks associated with caffeine. In adults, caffeine can lead to nervousness, insomnia, cardiac arrhythmia, increased blood pressure and gastrointestinal problems.

For adults, the consumption of up to 200 mg of caffeine within a short time is seen as safe. This is roughly the equivalent of two cups of filter coffee. In the course of a whole day, adults can drink about twice as much. Pregnant and breastfeeding women should drink no more than two cups of coffee whereas children should avoid coffee altogether. Sensitivity to coffee can vary greatly between individuals. Thus even one cup of coffee can lead to insomnia in some people. Sensitive people should refrain from consuming coffee, especially in high doses.

About the BfR

The German Federal Institute for Risk Assessment (BfR) is a scientifically independent institution within the portfolio of the Federal Ministry of Food and Agriculture (BMEL) in Germany. It advises the Federal Government and Federal Laender on questions of food, chemical and product safety. The BfR conducts its own research on topics that are closely linked to its assessment tasks.